1 photo
Quantum Energy AC4 Compact 270L

Quantum Energy AC4 Compact 270L

2.2 from 13 reviews

See the Best Gas Storage in 2019 as rated by Australians on ProductReview.com.au.

The Heat pump failed after 15 months

The compressor died after 15 months still in warranty and the service to have the part replaced is completely terrible with still waiting no tracking or timeline when it will arrive or be fixed for Hot Water no answer on 1800 number only voicemail

Purchased in January 2018 at Plummber for $2,500.00.

Build Quality
Value for Money
Cleaning & Maintenance
Noise Level
Household Size 5 person(s)
Smells of GasNo
Temperature Consistency
Heating Speed

OUCH!! stung again

Apparently a short life span on these units seems quite common. Ours is not even 5 years old and now dead. I had a perfectly operational element unit removed to be replaced with this. Disappointed would be an understatement, it feels as though I have been conned by a travelling salesman. Save your money and by something with a good reputation.

Purchased in September 2014.

Smells of GasNo

Piece of cow manure

Purchased unit in Nov 2015 now May 2019 the compressor dies of course only two year warranty what a waste of money and time. Would never recommend this product to anyone

Purchased in November 2015 for $4,500.00.

Build Quality
Value for Money
Cleaning & Maintenance
Noise Level
Household Size 5 person(s)
Smells of GasNo
Temperature Consistency
Heating Speed

One of the most efficient heat pumps

I've had the Quantum Compact 270 heat pump for almost 2 years and it's worked perfectly. I configured the inbuilt timer to come on during the daytime when it's the most efficient (the warmer the air, the less electricity they use) and when I'm generating electricity with my solar PV. At a COP of 4.5 (1 kWh of electricity gives 4.5 kWh of water heating), it's the second most efficient heat pump you can buy - meaning it has one of the highest rebates - I got $1200 back. It's pretty quiet at 48 dB (my aircon is 66 dB - 4 times louder) but I always run it in the daytime - I can't hear it then anyway. It works well when we have guests who shower a lot. It will take about 4 hours to heat up the whole tank from scratch but most days it only runs for a bit over an hour (when there's only 2 of us), using about 1.5 kWh of electricity, compared to 6 or 7 kWh for the old electric HWS. The tank seems to be very well insulated compared to other HWS.

Date PurchasedMar 2017

Don’t bother

After just over 2yrs old, just out of manufacture warranting the compressor is making such loud noises it’s unusable. Rang warranty and it’s pathetic of only 2yrs warranty. Refrigeration tech came to look and it appears it’s not worth replacing or fixing a compressor as it’s neqlry as expensive as getting a whole new product. Ironic thing is I never wanted this when building the new house 2yrs, 4 mths ago. I wanted an electric hot water system but building said we can’t in a new house and needed something Energy. Well after this expensive lesson I now need to completely rewrite etc to have electric one put in as I’d never get a heat pump again. Way too noisy!! Don’t bother, it’s not that much you save on power bill, way more expensive when you have to replace a whole until after 2yrs!

May 15th 20187 Update: Nothing but issues.

Died after not long after 2yrs old. Wouldn’t recommend a heat pump at all. Just look at all the bad reviews. Noisy and unreliable. Has costed us a fortune and it’s shoudn't has been costing us hardly anything but maybe some services in the first 10yrs but after not even 2.5yra it’s ceased up.

Date PurchasedDec 2015

Works well but is noisy

Built the house 18 years ago and installed a Quantum 270 litre unit (not sure of the model number) in the new build. It worked well for 12 years then developed a leak so needed a replacement. Replaced with a similar model 270-AS4 at my cost (around $3,000 from memory) as this would fit into the laundry cupboard where the original was located. The old system had a passive radiator which was no longer made so needed to install a fan unit on the roof to replace the old radiator - no biggy. The new unit worked fine for 3 years then it too developed a leak. This unit was replaced under warranty after some minor delays in getting plumbers to site. Then about 2 years ago the unit failed to start and after getting the plumber/aircon guys (Platinum Hot & Cold) out, the control board was replaced. This was also replaced under the 5 year warranty (just), so any more issues will cost me. The unit works well for me, but is a bit noisy in operation as it is installed indoors in a cupboard in the laundry that doubles as a clothes airing cupboard. Overall I have been fairly happy with the limited contact I have had with Quantum and the product heats the water at minimum electricity cost. The plumbers I have spoken to however are not enamoured with heat pump products in general, but say that Quantum are no worse than the rest.

Date PurchasedMar 1999

inferred warranty

If you want a quantum product don't expect more than 5 years use out of it.. Ours started rusting within twelve months, and they won't even reply to emails or phones calls. They assured me it we would get ten to fifteen years use, out of the over four grands worth of heater, we got less than six years.. This is one Company I would steer well clear of, if you want a reliable honest deal. It definitely won't be from them..

Date PurchasedNov 2011

One word!.. DONT

Quantum is the most ignorant Co. I have ever had the misfortune to deal with, They don't back up their products, they NEVER return promised calls or answer emails.. I would use cold water before wasting money on their products. Treating customers who have spent hard earned money on their heat pumps, the way they do is nothing short of disgusting..

Date PurchasedNov 2011
1 comment
A quantum manager, of some sort rang, me seven weeks after my first contact, after reporting them to the ACCC, to tell me they would NOT do anything about the crap water heat pump they foisted on me.. I asked him "why had he rang then".. His reply made me chuckle.. "Customer relations" he said.. My advice to anyone thinking of installing a heat pump is to stay well away from these no hopers..

Quantum Heat Pump

Just received a letter dated 23/12/16 saying that my Quantum Heat Pump is now ten year old and that it might require additional service or replacement. When is is replaced, it will NOT be with a Quantum product. I have had to spend a fortune on repairs ---$247.50 on 5/4/13, $375 on 21/3/14, and $700 on 6/5/15. My previous off-peak service went 19 years without a call out

Date PurchasedSep 2007

Awesome investment, Highly recommeded

I had a gas storage hot water system. The gas bill was so high upto 300 dollar. I have get plumber to install the quantum heat pump hot water system. 270L. I am so happy. My electric bill does not gone high as I was afraid of and my gas bill gone low to 40 dollars. This product is very reliable and highly recommended.

Date PurchasedAug 2016

Not worth the money

First impressions were good. Good savings on power bill after an initial outlay of $4500.00 it had just paid for its self after 6 a d a half years.
We fisr noticed our water pump cutting in and out a short an regular intervals, thinking we need to replace our pump after 20 years (can live with that) we then noticed a leak in our heat pump. Need a new heater there goes the savings. Were too from here?

Date PurchasedJul 2011

Extremely Corroded after 3.5 years

Hot water is cheap and the noise isn't really an issue for us BUT we have it on side of the house under the eaves and out of the elements and have just had a technician replace the temp sensor saying the tank is on its way out due to corrosion. These units must have an issue with electrolysis as they require a sacrificial anode. The anode needs to be checked yearly as if this is completely gone, the tank will go in a matter of months. I have just had arguments with Qantum and they have now agreed to replace the tank under warranty as it is likely to begin leaking soon and has caused other parts to malfunction. The customer service rep says this type of corrosion is expected and seen on most of the units, which is ridiculous! Clearly a design fault with the unit as they are likely to fail just after the 5 year warranty expires. If you know your rights under consumer laws it's ok but I am sure a lot of people just accept the manufacturer's word and replace at cost. (reasonable to expect this unit will last longer than the 5 year at the price point).
All in all, efficient hot water but need to keep it maintained. Surely other suppliers have sorted corrosion issues on the tank.
I wouldn't buy one again.

great unit.....would support any progressive technologies

Wouldn't go back to gas storage, instant gas or elemental electric
This thing produces endless hot water for my medium size family
12 months on and hasn't disappointed us yet

See all Quantum Energy AC4 Series reviews

Questions & Answers

How to adjust water temperature
1 answer
I have an AC6. As far as I know you shouldn't be able to adjust the temperature on storage HWS of any kind. Australian standards say it must be fixed at that temperature (60c, I think) to avoid Legionaires disease.

Can you change the water temperature?
2 answers
I think a technician may be able to do it by removing the top cover and adjusting the readout.. please contact a technician. other than a quantum that is!. I don't fancy your chances of getting a reply from Quantum though. They are the most unhelpful people I have ever had dealings with..On the left of the unit is an orange circular cover. There should also be a triangular key attached to the side of the unit. Under the orange cap is a brass triangular screw. Use the key to adjust this brass screw. You only need to turn this screw about one quarter of a turn. If you have heating problem it may be loss of refrigerant gas in which case it should be topped up by a licensed refrigeration technician..

Stops working when the temperature is too hot. Any ideas?
2 answers
The outside air temperature? Man, that's weird...I wish I could help, that sounds like a temp sensor issue but don't quote me on it, sorry.perhaps it is the temp sensor? you could try shading the unit and make sure it is well ventilated. You should try the q and a on the quantum web site.


AC4 Compact 270L
Release dateApr 2010
Compare all Quantum Energy AC4 Series
Visit official website

ProductReview.com.au has affiliate partnerships. These do not influence our content moderation policies in any way, though ProductReview.com.au may earn commissions for products/services purchased via affiliate links.